Vortex generator jets - Means for flow separation control

AIAA Journal ◽  
1990 ◽  
Vol 28 (6) ◽  
pp. 989-994 ◽  
Author(s):  
James P. Johnston ◽  
Michihiro Nishi
Keyword(s):  
Flow Separation ◽  
Vortex Generator ◽  
Separation Control ◽  
Flow Separation Control ◽  
Vortex Generator Jets

Study on Flow Separation Control by Vortex Generator Jets with Different Parameters

2012 ◽  
Vol 588-589 ◽  
pp. 1786-1789
Author(s):  
Yong Hui Xie ◽  
Zhong Yang Shen ◽  
Tao Fan
Keyword(s):  
Flow Control ◽  
Flow Separation ◽  
Vortex Generator ◽  
Separation Control ◽  
Flow Separation Control ◽  
Profound Influence ◽  
Orthogonal Analysis ◽  
Conical Diffuser ◽  
Flow Charts ◽  
Vortex Generator Jets

In order to investigate the mechanism of flow separation control in conical diffuser by vortex generator jets (VGJs) method, numerical simulations were conducted to discuss the effect of VGJs with different parameters on flow control. The aerodynamic performance in conical diffuser with angle of 14° was tested and analyzed based on Shear-Stress-Transport (SST) simulation. The flow charts at several sections were analyzed, illuminating the formation of complex vortices. Moreover, the effects of 5 VGJs parameters on the diffuser were analyzed by orthogonal analysis. It was shown that the number of jets and the pitch angle of jet showed more profound influence on the flow control by VGJs.

Numerical Investigations of Flow Separation Control for a Low Pressure Turbine Blade Using Steady and Pulsed Vortex Generator Jets

2010 ◽  
Author(s):  
Xiaomin Liu ◽  
Haiyang Zhou
Keyword(s):  
Turbine Blade ◽  
Flow Separation ◽  
Vortex Generator ◽  
Suction Side ◽  
Low Pressure ◽  
Pulse Frequency ◽  
Separation Control ◽  
Flow Separation Control ◽  
Low Pressure Turbine ◽  
Vortex Generator Jets

This paper investigated numerically the application of Vortex Generator Jets (VGJs) to control flow separation on the suction side of a low pressure turbine blade. Firstly, numerical simulations of flow separation for a LPT blade, which based on Menter’s SST k-ω turbulence model coupled with Langtry-Menter transition model, were performed for different Reynolds numbers Re∼100,000, 75,000, 50,000 and 25,000, for three freestream turbulence intensity (FSTI) of 0.08%, 2.35% and 6.0%. The pressure distributions around the turbine blade and streamline plots showing the flow separation were presented in this paper. Good agreement of the numerical and experimental results also showed the validity of the numerical scheme for simulating the flow separation occurring on a low pressure turbine blade. And then, steady Vortex Generator Jets (steady VGJs) having pitch angle of 30°, skew angle of 90°, blowing ratio of 2.0 were used to control the flow separation in the suction side of the low pressure turbine blade. Although steady VGJs have been illustrated to be extremely robust at suppressing low Reynolds number separation, the practical application of VGJs in the low pressure turbine engine is in the pulsed mode. The injection mass flow requirements of pulsed Vortex Generator Jets (pulsed VGJs) can be reduced drastically when similar flow control effect is obtained using steady VGJs. For pulsed VGJs, the pulse frequency has been found to be an important control parameter for the flow separation control. In this paper, cases with the duty cycle of 0.5 were studied for the pulse frequency ranging from 2.5Hz to 10Hz at Re = 25,000 and freestream turbulence level of 0.08%. The numerical results showed that pulsed VGJs can effectively reduce and even eliminate the flow separation on the blade suction surface while there is an optimal pulse frequency. The flow control mechanism of VGJs on LPT blade was also revealed.

Active Flow Separation Control Using Endwall Vortex Generator Jets in Highly Loaded Compressor Cascades

2015 ◽  
Author(s):  
Yanyan Feng ◽  
Yanping Song ◽  
Fu Chen ◽  
Huaping Liu
Keyword(s):  
Flow Separation ◽  
Active Flow Control ◽  
Vortex Generator ◽  
Control Technique ◽  
Flow Separation Control ◽  
Positive Effects ◽  
Loss Coefficients ◽  
Vortex Generator Jets ◽  
Active Flow ◽  
Highly Loaded

An active flow control technique of endwall vortex generator jets (VGJs) was used in two kinds of highly loaded compressor cascades. Numerical investigations were carried out on a NACA 65 profile with a large camber angle at low subsonic and high subsonic speeds, and a CDA profile at high subsonic speed respectively. The results indicate that the endwall VGJs can restrain flow separation effectively by reenergizing the boundary layer fluid and resisting the transverse movement of endwall secondary flow. At Mach number 0.23, the results of the jet blowing ratio study illustrate that the increasing jet velocity shows noteworthy potential to improve the cascade aerodynamic performance. The double jets structures were investigated yet gains weaker beneficial effects than single jet. It is probably attributed to the complex flow structure, leading to strong disturbance and large-scale mixing loss. Under −5°, 0° and +5° angles of attack, the loss coefficients are maximally reduced by 4.1%, 9.5% and 17.3% respectively. Under high subsonic conditions, the endwall VGJs still has significantly positive effects on NACA 65 profile. Considering the small separation region of CDA, the loss coefficients increase slightly although the flow separation is weakened further by VGJ.

Statistical Vortex-Generator-Jet Model for Turbulent Flow Separation Control

AIAA Journal ◽  
2013 ◽  
Vol 51 (5) ◽  
pp. 1119-1129 ◽  
Author(s):  
Florian von Stillfried ◽  
Stefan Wallin ◽  
Arne V. Johansson
Keyword(s):  
Turbulent Flow ◽  
Flow Separation ◽  
Vortex Generator ◽  
Separation Control ◽  
Flow Separation Control ◽  
Vortex Generator Jet
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